I have a set of 400 Heads that have 76cc Chambers and i want to get them down to 70cc's. How much do i shave the heads to get them down to 70cc's.

 

I believe that the general rule is .006" for every 1cc. So .036" should do the trick. Why do you want to mill them? A better option the milling would be to start with some L98 or some 64cc 350 heads and port the chamber to your desired size.

 

I agree with leigh, those heads you have (if stock heads) are probably junk, and not worth the price to mill them.

otherwise, i'd just leave the heads at your machine shop, and tell them to "mill the heads to 70cc's" and let them worry about the #'s.

 

I'm milling them for higher compression. The only reason i want to use these heads because they are in good shape and have 1.94 and 1.56 valves. I asked the guy at the machine shop how much to mill them and he says he cant cc the chambers so he didnt know.

 

If thats the case. You would be better off buying some 64cc chamber 350 heads that are in good shape. It will cost the same or maybe less if they don't need work. 400 heads are just about the worst out there.

 

...your machinist "can't" cc your heads? hmmm

 

It's probably not a performance shop by any means. It's probably just your average, get it done as fast can low quality place.

 

I have a set of center bolt iron l98 heads if your interested. Came off a remanufactured roller block 350 engine, a piston crack inside the engine when it was still under warranty and the owner sold it to me cheap. The heads are just sitting in my shop.